At present, a resistive random access memory (ReRAM) is a novel Non-volatile memory device which stores information by using a change in a resistance value, and has the advantages of high operation speed (<5 ns), low operation voltage (<1V), high storage density, and easy being integrated etc. Thus, the resistive switching memory is a prospective candidate for the next-generation semiconductor memory.
The storage unit of the resistive switching memory device typically has an metal-insulator-metal (MIM) configuration in which a medium thin film material having a variable-resistance characteristic is sandwiched between two metal electrodes. The variable-resistance material is typically a metal oxide, such as NiO, TiO2, HfO2, ZrO2, WO3, Ta2O5, or the like. The resistive switching memory devices can be classified as unipolar or bipolar devices according to its operation scheme. As for the former, a unipolar voltage is applied across a resistive switching memory device, and a resistance value of the variable-resistance material is transited between a high-resistance state and a low-resistance changes with different amplitudes of the externally applied voltage to write data into the resistive swithcing memory device or erase data therefrom. As for the latter, voltages having different polarities are applied across the resistive swithcing memory device to control the transition of the resistance value of the variable-resistance material. Typically, a change from the high-resistance state to the low-resistance state of the variable-resistance material is referred to as PROGRAM or SET operation, and a change from the low-resistance state to the high-resistance state of the variable-resistance material is referred to as ERASE or RESET operation.
Although the resistive switching memory have many advantages, the erasing times (transition times) of it is required to reach at a certain order of magnitude such as above 1012, in order to satisfy the requirements of the general memories. However, the erasing times (transition times) of the present resistive switching memory is under 109.